Preheat the oven to 375℉.
Cook pasta according to package directions. Drain and pour into a casserole baking dish. Add the shredded chicken on top of the noodles.
While the pasta cooks, melt 2 tablespoons butter in a saucepan. Whisk in flour to form a paste. Slowly whisk in chicken broth and milk. Add chicken bouillon, Dijon mustard, Worcestershire sauce, all seasonings, and both cheeses. Continue whisking until cheese is fully melted into the sauce. If sauce is runny, bring to a boil and add a tablespoon of cornstarch.
Add frozen peas and carrots to the sauce and stir. Pour the sauce over the chicken and noodles in the baking dish. Carefully stir to combine.
Combine panko breadcrumbs and olive oil in a small dish. Sprinkle the breadcrumbs on top of the casserole.
Bake in the oven for approximately 25 minutes until the sauce is bubbly. If desired, brown the breadcrumbs on top under the broiler for 1-2 minutes.
